A new study of insect numbers across the globe says that declining insect numbers are threatening a ‘collapse of nature’ unless something is done to address the issue. Over the next few decades, up to 40% of the world’s insect species could be wiped out.
The study, ‘Worldwide decline of the entomofauna: A review of its drivers‘ and published in the journal, Biological Conservation, looked at 73 historical studies of insect declines. It found the main drivers of plummeting insect numbers as: i) habitat loss and conversion to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change
Climate change was an important driver in tropical regions and widespread pesticide use in nearly every area of agricultural production was having a huge impact. 41% of all insect species were in decline.
In its recommendations, the study calls for “a rethinking of current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices…”
To put the estimated decline in the study of 2.5% per annum into perspective, it means that after 10 years, there would be a quarter less insects, in 50 years only half left and in 100 years, none.
The loss of insects would have the biggest impact on birds, reptiles, amphibians and fish that eat them, potentially removing insects as a food source with a huge knock-on effect right across the food chain. If all of this seems that it is happening in some far-off place, the UK has lost 58% of its butterfly species in the ten years to 2009. In France, the collapse of many bird populations was linked to widespread and relentless pesticide use in agriculture.
The study warns that “Unless we change our way of producing food, insects as a whole will go down the path of extinction in a few decades…”with the authors warning that we are “witnessing the largest extinction event on Earth since the late Permian and Cretaceous periods.”